1. Field of the Invention
The present invention relates to a hybrid vehicle having an engine and a primary motor as a drive source for running the vehicle, and a secondary motor used for any other purposes than as the drive source for running the vehicle, and a method for controlling the hybrid vehicle.
2. Description of the Related Art
Hybrid vehicles are known in which a running motor is connected to main driving wheels which are driven by an engine, or in which a running motor is connected to sub driving wheels which are disconnected from the engine. In these hybrid vehicles, fuel consumption can be saved by driving the running motor singly to run the vehicle, by running the vehicle while causing the running motor to assist the engine in driving the vehicle, or by causing the running motor to function as a generator to perform a regenerative braking operation when the vehicle is decelerated so that kinetic energy of the vehicle is reclaimed and stored as electric energy.
Incidentally, with a view to saving the fuel consumption further, in case an engine “idling Stop” control is adopted to stop the engine when the vehicle comes to a stop, the compressor for the air conditioner and the hydraulic pump which are driven by the engine are also stopped, which leads to problems that the comfortableness of passengers in the vehicle is deteriorated while the idling stop is being implemented and that the rise of oil pressure is delayed when the vehicle is started from rest, whereby a smooth start of the vehicle is interrupted.
Then, it is conceived that auxiliary units such as the compressor and the hydraulic pump which are driven by the engine in related art are driven by auxiliary unit motors. However, in case an inverter is needed for each auxiliary unit motor, several inverters need to be provided in addition to one for the running motor. With the aforesaid related-art hybrid vehicle, however, since an electric oil pump is needed in addition to the oil pump driven by the engine, there is caused a problem that the number of components, costs, space and weight are increased.